Improvement in devices to prevent boiler-explosions



UNITED STATES PATENT OFFICE@ ALFRED ARNOLD, OF TENAFLY, NEW JERSEY.

IMPROVEMENT IN DEVICES TO PREVENT BOILER-EXPLOSIONS.

Specification forming part of Letters Patent N0. 55,801, dated June 26,1866.

To all whom 'it mor/y concern: h

Be it known that I, ALFRED ARNOLD, of Tenafly, in the county of Bergenand State of New Jersey, have invented a new and useful Mode ofPreventing Steam-Boiler Explosions; and I do hereby declare that thefollowing is a full and exact description thereof.

Experimental science has developed two causes, either of which, underthe requisite conditions, are capable of producing terrific explosions.

The first and popular theory is that relating to the spheroidal state ofWater when in contact with extremely hot metal, as when from low waterthe lines or other portion of the interior of the boiler become dry andunduly heated and are then flooded.

The second cause is the increased cohesion of the particles of waterwhen purged of air, which, under the lnost favorable circumstances forsuch an event, admits its temperature to be raised more than 100O abovethe boilingpoint at that pressure, and then ebullition necessarilycommences with explosion. rEhis second cause, though less familiar tothe public than the lirst, appears to be more consistent with theconditions under which explosions usually occur.

My invention applies equally to either or both these theories, and toany and all others founded on the only rational hypothesisnamely, thatexplosions (not merely straining open of a weak boiler) occur from adegree of heat in some part of the boiler far above that due to thepressure therein.

The nature of my invention consists, first, in the employment of suchthermometric devices as will give seasonable warning of danger wheneverthe water or that portion of the boiler to which they are appliedbecomes hotter than is due to the pressure, whereby the person inattendance may extinguish the fires or use such other means as he maythink proper to prevent the catastrophe; and, second, in such acombination of devices as will give an alarm whenever the water or thatportionof the boiler to which they are applied becomes hotter than isdue to the pressure therein, but will disregard any variation in thetemperature when accompanied with its corresponding pressure.

lo enable others to use my invention, I will describe the devices andtheir operation.

Though my invention may be employed by the use of detached devices, suchas athermometric and pressure device or two thermometric devices soarranged that any variation in their several motions will produce asingle resultant motion, I prefer the arrangement shown in the drawing,which is a longitudinal section of an instrument wherein all therequisites to illustrate and carry into operation the whole nature of myinvention are combined in a simple and compact form.

A is a series of hollow elastic disks filled with water or other liquidWhose boiling-point corresponds with that of water. If water isemployed, it should be aerated or hold its full complement of air insuspension.

B is a small tube, one end open and the other closed. The lower orclosed end is firmly attached to the exterior of A, and the upper oropen end is closely fitted to but slides Vfreely in a perforation in C.b b are small to the plug C and cross-head E. The latter is made fast toA.

This .instrument should be applied through a perforation in the top ofthe boiler prepared to receive the thread of the plug C. rllhe tube Band rods D D should be of sufficient length to carry A below thewater-line, and so near that portion of the surface of the boiler orliue most likely to be unduly heated that it will be actuated at suchtimes by the radiation or conduction of the metal. The exact locality ofthe instrument must depend on the kind of boiler to which it is applied,and will be determined by the user in accordance with theseinstructions.

Its operation is as follows: So long as the temperature in the boilercorresponds with the pressure the pressure in the instrument willexactly balance that in the boiler; but should the temperature of thewater in the boiler exceed that due to the pressure, or should thatportionof the surface of the boiler or iue in proximity to A be dry, andthus become unduly heated, then the pressure in A will exceed that inthe boiler, and the elastic disks will yield to the internal pressure,forcing the end of B into G until b reaches the point o, when steam fromthe boiler rushes through b into B, 2. The construction and arrangementof the and through b and c into a steam-Whistle, (not devices necessaryto carry the mode into opershoWn,) thus giving a constant alarm untiltion, substantially as described. the danger is averted.

What I claim as my invention, and desire ALFRED ARNOLD' to secure byLetters Patent7 is Witnesses:

l. The mode of preventing steam-boiler 'eX- HENRY STANTON, plosions,substantially as herein set forth. CHARLES SEIBOLD.

